Another window we examine in detail is for \(M_{Z^{\prime }}\)  above an MeV, as shown in Fig. REF .
Most of the constraints in this plot are translated from those for the dark photon searches [1]}.
The green, blue and gray regions are excluded by BaBar , electron \(g-2\)  and electron beam dump experiments.
Unlike the dark photon, our \(Z^{\prime }\)  also has a branching ratio to neutrinos which affect the branching ratio of its visible decay. We take this into account when translating the limits.
Interestingly, we find that there is a mass window, with \(10\,{\rm MeV}< M_{Z^{\prime }} <200\,{\rm MeV}\) , where the neutrino experiments can do better than other experiments.
This point was made in a similar model in [2]}.
